This work investigates alterations in activity or concentration of various enzymes and substrates of the brain in response to episodes of anoxia or hypoxia. Changes in content of water and electrolytes also are examined in cortex, basal ganglia, and hemispheral white matter. Tissues are examined during episodes of anoxia and hypoxia and also following resuscitation and concentrations in the brains of animals that develop brain edema and those that recover normally.